Field of the Invention
The present invention relates, in general, to a hydrogen sensor.
Description of the Related Art
Generally, hydrogen energy has been actively studied since it is reusable and has an advantage in that it does not induce environmental pollution.
However, since hydrogen gas runs the risk of explosion if exposed to air by 4% or more, it is difficult to widely apply hydrogen gas in our real life if safety-in-use is not secured. Therefore, along with the studies on utilization of hydrogen energy, a hydrogen gas-detection sensor (simply referred hereinafter to as a ‘hydrogen sensor’) has been developed in order to, in practical use, detect leakage of the hydrogen gas in early stages.
In the meantime, as hydrogen energy is availably commercialized, it is expected to be first applied to the automobile markets. Considering that researches are currently carried out on loading compressed hydrogen gas on an automobile, there is a need to develop a hydrogen safety sensor that can be adapted to a fuel supply and an electronic unit so as to detect leakage of hydrogen. Further, the hydrogen sensor is essentially required for the detection of leakage of hydrogen, monitoring of a hydrogen concentration, or the like, as a component of hydrogen storage and supply systems in a hydrogen fuel cell-activated unit. In addition, a hydrogen sensor is often used to detect a gas-leaking portion using hydrogen gas, rather than conventionally using helium gas, in an air-conditioner, refrigerator or the like, which uses a coolant, in order for more precise detection.
In regard to such a hydrogen sensor, a hydrogen sensor is known in which a Pd thin film (TF) or Pd alloy TF is disposed on an elastic substrate, and nanogaps are formed in the TF by extension of the substrate, and hydrogen is detected using the nanogaps (see Korean Patent Registration No. 10-1067557). However, such a hydrogen sensor is the type of sensor that detects hydrogen using a change in current, so a signal from the sensor can be recognized only when the hydrogen sensor is coupled to a computer or the like and electric current detected from the hydrogen sensor is converted into a voltage. A conventional hydrogen sensor, however, has a problem of a low current signal. That is, a specific reference voltage is required in order to check whether a voltage signal indicates an ON or OFF state. However, in a conventional hydrogen sensor, a current signal induced from a low hydrogen concentration is so low that, even when converted into a voltage signal, it is difficult to check whether the converted voltage signal indicates an ON or OFF signal.